Nowadays, there are many techniques developed for obtaining a wider viewing angle of the liquid crystal display (LCD). Among so many wide viewing angle (WVA) techniques, the vertical alignment (VA) techniques including a multi-domain vertical alignment (MVA) LCD, a patterned vertical alignment (PVA) LCD and a biased bending vertical alignment (BBVA) LCD are widely applied.
Among the mentioned VA techniques, the MVA technique utilizes the properties of the non-identical directions in arrangements and rotations of the liquid crystal (LC) molecules to increase the viewing angle and shorten the response time of the LCD. For example, the LC molecules arranged in the MVA LCD could be promoted to align in various directions by the surface prominence, such as bumps and protrusions. As for the PVA LCD, which is another application in the MVA techniques, the pixel thereof is divided into multiple domains by a patterned indium tin oxide (ITO) on the color filter (CF) substrate. Furthermore, the BBVA technique relates to adjusting the arrangements and rotations of the LC molecules in various directions by means of the electrical field provided by a further electrode, i.e. the biased electrode.
However, there are still some issues affecting the image property of the conventional multi-domain vertical alignment mode LCD, and one of which resides in the pressure mura resulting from the disclination of LC molecules. Take the BBVA LCD for example, the disclination phenomenon occurs because the LC molecules arranged in the sides of the pixel electrode paralleled to the scanning lines or data lines, i.e. the pixel wing as respectively shown in area I of FIG. 1, always tilt in conflicting directions.
With reference to FIG. 2, which is a diagram illustrating the root cause of the reverse domain of the conventional BBVA LCD and the pressure mura observed in the pixel structure thereof, the pressure mura as shown is referred to two different cases, where one relates to the conflict of LC molecules resulting from the structure of pixel electrode, as shown in areas I″ and II″, and the other relates to the intrinsic shift of LC molecules accordingly, as shown in areas I′ and II′ thereof. As a result, the LC molecules will be aligned disclinatedly on the fringe of the overlapping field of the biased electrode and the pixel electrode of the conventional BBVA LCD, and the reverse domains and thus the pressure mura and lower transmittance would be generated correspondingly.
In order to overcome such issues of the conventional VA LCD, an improved VA LCD having a new pixel structure is provided in the present invention, whereby the disclination lines thereof would be efficiently removed and the pressure mura resulting therefrom is hence prevented.